In the manufacture of semiconductors and semiconductor microcircuits, it is frequently necessary to coat substrate materials with a polymeric organic substance. Examples of some substrate materials includes, aluminum, titanium, copper, silicon dioxide coated silicon wafer, optionally having metallic elements of aluminum, titanium, or copper, and the like. Typically, the polymeric organic substance is a photoresist material. This is a material which will form an etch mask upon development after exposure to light for photolithography. In some cases, the photoresist layer needs be reworked. In subsequent processing steps, at least a portion of the photoresist is removed from the surface of the substrate. One common method of removing photoresist from a substrate is by wet chemical means. The wet chemical compositions formulated to remove the photoresist from the substrate should do so without corroding, dissolving, and/or dulling the surface of any metallic circuitry; chemically altering the inorganic substrate; and/or attacking the substrate itself. Another method of removing photoresist is by a dry ash method where the photoresist is removed by plasma ashing using either oxygen or forming gas, such as hydrogen. The residues or by-products may be the photoresist itself or a combination of the photoresist, underlying substrate and/or etch gases. These residues or by-products are often referred to as sidewall polymers, veils or fences.
Increasingly, reactive ion etching (RIE), is the process of choice for pattern transfer during via, metal line and trench formation. For instance, complex semi-conductor devices, such as advanced DRAMS and microprocessors, which require multiple layers of back end of line interconnect wiring, utilize RIE to produce vias, metal lines and trench structures. Vias are used, through the interlayer dielectric, to provide contact between one level of silicon, silicide or metal wiring and the next level of wiring.
Metal lines are conductive structures used as device interconnects. Trench structures are used in the formation of metal line structures. Vias, metal lines and trench structures typically expose metals and alloys, such as Al, Al and Cu alloys, Cu, Ti, TiN, Ta, TaN, W, TiW, silicon or a silicide such as a silicide of tungsten, titanium or cobalt. The RIE process typically leaves a residue or a complex mixture that may include re-sputtered oxide material, organic materials from photoresist, and/or antireflective coating materials used to lithographically define the vias, metal lines and or trench structures.
It is desirable to provide a cleaning formulation and process capable of removing those unwanted materials without corroding, dissolving or dulling the exposed surface of the substrate. In some instances the unwanted materials are polymeric compositions referred to as photoresists. In other instances the unwanted materials to be removed are residues of etching or ashing processes or simply contaminants.
Patents in this technological field include U.S. Pat. Nos. 6,627,587, 6,723,691, 6,851,432 to Naghshineh et al., and published patent application US2006/0016785.